PORTLAND, Maine — The final say on the public health risks of “smart meters” lies with the state supreme court.

After opponents of a Maine Public Utilities Commission decision on the safety of the electricity meters filed an appeal with the Supreme Judicial Court in May, the PUC and Central Maine Power Co., the utility that covers most of western Maine, filed opinions with the court defending the PUC ruling.

At issue are the alleged health risks caused by the radio-frequency radiation emitted by CMP’s smart meters, which transmit usage information wirelessly between a customer’s home and the utility.

Opponents argue that the effects of exposure to continual low-level radiation range from nausea to cancer.

But in December 2014, the PUC ruled that smart meters do not “present a credible threat to the health and safety of CMP’s customers.”

The decision came after a 2 ½-year investigation into the alleged health risks of the meters, with significant input from both CMP and the opponents Ed Friedman and the Maine Coalition to Stop Smart Meters.

Friedman appealed the PUC’s December ruling to the high court in May, arguing that a PUC decision “can be vacated when it is unreasonable, unjust, or unlawful in light of the record.”

Friedman and other appellants point to what they see as a conflict in the PUC’s written ruling.

The PUC is made up of three commissioners, appointed by the governor. The smart meter decision reflected the decision of Commissioners Mark Vannoy and David Littell, since then-Chairman Tom Welch recused himself on the basis of prior employment with CMP.

Although the final ruling states no credible threat of harm, in Littell’s individual opinion, he wrote “If limited RF… exposure is recommended by a doctor or medical practitioners, I would address the pending complaint by allowing for a … (meter to be) turned off at the ratepayer’s primary residence at no cost.”

Friedman and the coalition argue that this statement acknowledges a safety risk associated with smart meters and that the opt-out rate – currently $40 up front and $12 per month to continue – is an unfair burden.

Both the PUC and CMP filed briefs with the court on June 30, standing by the original decision.

Attorneys for the PUC said that despite different “analytical” approaches, commissioners Littell and Vannoy reach the same conclusion of no threat of harm.

“Mr. Friedman would have the Court focus on this one clause and allow it to overshadow the entire seven-page section of Commissioner Littell’s concurrence … where (he) discusses medical opt-outs,” they argue.

The PUC also maintains that their more than two-year investigation into the arguments of both sides, as well as a significant review of scientific literature, shows the decision is based on “substantial evidence in the record.”

CMP’s brief, filed after the commission’s, said the court should not even agree to hear the case, arguing that the jurisdiction is federal.

The Federal Communication Commission sets guidelines for RF radiation from devices like cell phones, Wi-Fi, and smart meters, and thus the “only relevant information” the PUC had authority to consider was if CMP’s smart meters met these guidelines, CMP argues.

Based on field studies conducted by the utility, the PUC found that emissions from smart meters are well below FCC standards.

“Appellants argue that the PUC and now the Court should look behind the FCC standards and conclude that the FCC standards are insufficient,” the opinion states. “Neither the PUC nor the Court has the capacity or, more importantly, the authority to do what Appellants request.”

Friedman and the coalition filed a final reply brief with the court July 14.

Bruce McGlauflin, attorney for the Friedman and the coalition, made an analogy to the legal battles over the safety of smoking in the 1960s, “when there was evidence but no scientific consensus, conclusive proof, or ‘known’ threat of cancer from cigarette smoking,” he said.

He argues that the situation with RF radiation may be even worse, saying “(companies) were not pumping cigarette smoke into people’s homes or charging them a monthly fee to avoid it.”

In an interview Monday, Friedman pointed to recent publications documenting radio-frequency radiation, including an article in the journal Electromagnetic Biology and Medicine documenting cell damage due to low-intensity RF radiation.

“If these things don’t present a credible threat, I don’t know what does,” he said.

The court will soon begin its August recess, so oral arguments are not expected to be scheduled until the fall, Friedman said.